This invention relates to alcohols and more particularly to energetic polynitroakyldiols.
The chief promise of energetic polynitrodiols for practical explosive applications are as monomers for the synthesis of hydroxy termined prepolymers. In practice, the prepolymers are mixed with a solid explosive, EQU HOCH.sub.2 . . . CH.sub.2 OH+X.sub.2 R.music-sharp.HO[CH.sub.2 . . . CH.sub.2 ORO--CH.sub.2 . . . CH.sub.2 ].sub.n OH
ex., RDX or HMX, an energetic plasticizer and isocyanate curing agents. The liquid slurry is then cast into a suitable mold and cured to form a rubbery matrix which not only binds the solid explosive and defines the shape, but also contributes energy to the final composition.
The most attractive diols from the standpoint of energy and availability are 2,2-dinitro-1,3-propanediol (A-diol) and 2,2,8,8-tetranitro-4,6-dioxa-1,9-nonanediol (DINOL). Both of these diols, as is the case with the majority of known polynitromonols, are substituted with nitro groups in the beta-position. Alcohols of this type are easily prepared by the addition of the respective nitrocarbanion to formaldehyde (Henry reaction). Unfortunately, however, ##STR2## this reaction is reversible in the presence of even mild bases and the resultant nitrocarbanion is subject to side reactions and decomposition over ##STR3## varying periods of time.
Energetic polymers that contain unreacted beta-nitro alcohol end groups are also subject to the reverse Henry reaction and under the conditions of isocyanate curing wherein basic urethane linkages are formed, decomposition can and does occur. This leads to poor thermal stability and aging characteristics. This is undoubtedly the reason why AFNOL, an energetic polymer, formed from pimeloyl chloride and DINOL was ultimately rejected as a candidate energetic polymer.
For this reason, a considerable effort has been expended among different groups to prepare energetic diols that are not subject to deformylation under basic conditions. These have been without exception straight chain diols, which generally, though not always, contain both nitramine and gem dinitro groups on the backbone. These structural characteristics lead to hard prepolymers with poor solubilities in the energetic plasticizers used in the explosive compositions. This type of diol appears to be of limited usefulness.